This invention relates to a clip attachment apparatus of the type for attaching U-shaped, metal clips about gathered material.
Various mechanism have been devised for the attachment of U-shaped, metal clips about gathered material. Typically, such mechanisms include, a frame with a clip channel passing vertically through the frame. A window is provided for feeding clips one at a time into the channel so that the clip may be engaged by a reciprocating punch. The punch is operated to drive the clips down the channel and against a die to thereby form the clip about gathered material positioned in the path of the clip. A gate mechanism is typically provided to define a portion of one side of the channel. The gate mechanism is typically pivotally attached to the frame so that the channel may be opened or exposed and then gathered material may be placed in the channel in the path of a descending clip.
Various mechanisms have been suggested for operation of the gate. For example, Klenz in U.S. Pat. No. 3,543,378, entitled Clipping Apparatus, disclosed opposed sliding plates or gate members which are spaced one from the other for insertion of material to be clipped. The gate members then slidably approach one another to compress and form the material. A clip is then driven down a channel defined in one of the gate members for forming about the gathered material. Velarde in U.S. Pat. No. 4,109,363 discloses yet another gate mechanism. In U.S. Pat. No. 4,109,363 a gate is pivotally mounted on the frame and is connected by a linkage to the drive piston which also operates the punch for driving the clip. The linkage ensures that the gate will be rotated to a closed position to form the channel before a clip is driven down the channel against a die. Conversely, when the punch has been retracted from engagement with a clip, the gate is swung open to reveal a throat for receipt of gathered material.
Evans in U.S. Pat. No. 4,675,945 discloses at pivotal or movable gate which pivots out of position to expose a throat for receipt of gathered material. The gate is pivoted by actuation of a separate control cylinder unassociated with the cylinder for driving the punch. Dobbert in U.S. Pat. No. 3,783,583 also discloses a gate mechanism which is associated with a separate cylinder actuator and which opens when the cylinder is in a retracted position and is closed to form the channel and gather material when the cylinder is in its extended position. Evans in U.S. Pat. No. 4,766,713 also discloses a gate mechanism which pivots in response to cylinder actuation. Seelly et al. in U.S. Pat. No. 4,993,135 disclose a gate mechanism which is manually actuated.
The referenced devices work well and provide generally an adequate mechanism for gathering casing material, defining a clip channel for receipt of a U-shaped metal clip, and for applying a clip about the gathered material. There has remained, however, the need for an improved gate construction associated with a clip attachment apparatus. The present invention comprises such an improvement.